Developers discover that Apple's new device required some creative rethinking

User experience (UX) designers don't just make pretty icons, though that certainly can be part of the job. Figuring out how people interact with data and interfaces means understanding ergonomics, psychology, computer science, cognitive science, graphic design and a number of other fields.

If you've ever been frustrated or confused when working with an application or a Web site, blame the UX designers. If the application seems like it "just works," then you can thank them.

While it may not be obvious to most technology users, each new form factor -- desktop, Web, mobile device -- requires a whole new set of research, testing and design principles.

Apple's recently released iPad is no exception; despite some snark that "it's just a ginormous iPhone," developers of iPad apps have found that the size does matter -- and that's in addition to the iPad's unique multitouch functions and interface elements. A properly designed iPad app is not just a pixel-doubled iPhone app, nor is it a desktop app with the mouse replaced by a finger.

I spoke with UX designers and product managers at two companies -- The Omni Group and Zinio LLC -- to find out more about the challenges they faced developing for the iPad. In particular, I wanted to know more about whether it confounded their initial design plans, or whether they were surprised to find new possibilities for user functionality.

'Room for content'

"First, we really found that it's not just a larger iPhone," said Ken Case, founder and CEO of The Omni Group. "There's room for content, and interaction with gestures, that you couldn't do on smaller real estate. It's a larger iPhone the way a swimming pool is a larger bathtub."

Initially, says Bill Van Hecke, Omni Group's UX lead, the company thought it would need to use every pixel on the iPad's 1024-by-768-pixel screen: "It was our first impulse to fill up the space, but we found in the design process that it was more important to see the content." As a result, he said, the user interface on the iPad for two Omni apps, OmniGraffle ($49.99) and OmniGraphSketcher ($14.99), takes up the same percentage of screen real estate as the company's iPhone apps.

For instance, initial interface designs for the apps included a sidebar that would show open documents and allow quick navigation among them -- a feature not unusual on desktop interfaces. But on the iPad, that felt like wasted space -- screen space was more valuable as free area for drawing.

"It was a good exercise in getting rid of our excess chrome [toolbar and window frames]," said Robin Stewart, lead developer for OmniGraphSketcher. "We think we ended up making this app more usable on the iPad than on a laptop."

Developers of The Omni Group's OmniGraphSketcher had to rethink user interface plans when designing for the iPad.